Field of the Invention
The present disclosure relates to a vibration drive system to be installed in the vicinity or in the interior of an apparatus configured to perform a diagnosis, measurement, and medical treatment using a magnetic field, or a medical apparatus and a medical system using the vibration type drive device.
Description of the Related Art
In recent years, study and development of an operation-aiding robot on the basis of an image feedback using a magnetic resonance imaging apparatus grow active in a field of medical-aiding robot. The magnetic resonance imaging apparatus of the related art performs an image diagnosis in the form of covering a body surface of a patient by a gantry having a cylindrical shape. In contrast, in recent years, an open magnetic resonance imaging apparatus having a gantry with a large opening or a wide space at a center portion of the gantry is developed, and a probability of interposition of the operation-aided robot or a medical practitioner into the interior of the magnetic resonance imaging apparatus is becoming higher. In contrast, a magnetostatic field in the magnetic resonance imaging apparatus is as very strong as 1.5 [T] to 3.0 [T]. In order to determine three-dimensional positional information in an image acquisition with high degree of accuracy in the interior of the magnetic resonance imaging apparatus, the magnetic field accuracy is controlled with very high degree of accuracy, and a gradient magnetic field which temporally varies in a triaxial direction is applied thereto. Therefore, when using a conductive material which forms a closed loop in the operation-aiding robot or other medical instruments to be brought to the vicinity of or in the interior of the gantry of the magnetic resonance imaging apparatus, Lorentz force generated by a variable magnetic field and an influence on magnetic field controlled with high degree of accuracy are required to be eliminated.
U.S. Pat. No. 6,274,965 B1 describes that components other than a housing in a vibration type drive device used near the magnetic resonance imaging apparatus are formed of a material which does not affect an image arch fact of the magnetic resonance imaging apparatus. Therefore, in U.S. Pat. No. 6,274,965 B1, an example of configuration in which titanium, tantalum, and aluminum as components of the vibration type drive device is disclosed.